If you want your cooktop in the middle of the kitchen and not against an exterior wall, and you want something that vents outside, then you're going to have to cut holes through the ceiling or floor to do it. You can install a hood that drops over the cooktop, and runs to the ceiling, where you have cut holes for the ductwork. You could just install fans like badge, and cut holes for the ductwork. Or you could get a downdraft range, which pulls the air across and down, and you'd have to cut holes in the floor and then run ductwork to the outside for proper venting. Obviously if you're on a slab that becomes problematic.